1. Not putting each other first.
Once you marry, make each other a priority. This doesn't mean sticking together like glue, however. Instead, think of your marriage and the rest of your obligations as a system of checks and balances. If you notice that all of your time is spent working or running after the kids, take time to rejigger a few things to make sure you actually spend time together that goes beyond crashing on the couch. Date night might sound cheesy, but it works.
2. Weak communication.
It's important to say things that are bothering you as they come up; otherwise, you're brewing a recipe for resentment and fights that have you literally crying over spilled milk—except it's not about the dairy. Screaming matches or shutting down and refusing to talk are equally unhealthy ways to argue. Learn to talk about disappointments without blaming.
3. Keeping secrets.
Make a point to talk about your day and worries, innocent as they may be. Perhaps you're self-conscious that you didn't get that promotion and now feel guilty because you self-medicated with retail therapy. Keeping mum about your shopping splurge is not healthy, as it can become habitual. Wouldn't you feel hurt if your partner told little white lies, too? Relationships are built on trust and if you can't own up to little things, it's going to be a lot harder to get the guts to tackle important conversations.
4. Poor boundaries with family or friends.
Family and friends have a time and a place and should not invade your life. Think: a pushy MIL who unexpectedly shows up for dinner three times a week or another couple who loves to brunch every weekend. While both groups of people are important, if either of you feels a bit claustrophobic it's time to learn how to say "no" to zealous guests. What's more, minimize conversations about your private life outside the marriage. Tempting as it may be to vent, the listening party will probably make a bigger deal out of your rant—you don't want mom thinking that your hubby is neglectful just because he had a period of late nights at work.
5. Never apologizing or admitting that you are wrong.
Love Story took the "Love means never having to say you're sorry" a bit too far. We're all adults here and if you do something wrong, or hurt feelings, you need to apologize. Sure, it's easier to make excuses for poor behavior, or worse, flip the situation and blame the other person, but you're not in kindergarten anymore.
6. Not showing gratitude.
Say "thank you" for the things your spouse is doing, even if they are expected, ahem, chores. Gratitude goes a long way especially when one of you is stuck doing something annoying, like filling out tax forms. Even if your partner enjoys mowing the lawn, don't underestimate the power of showing appreciation for perfectly manicured grass.
7. Exerting jealousy.
There is a big difference between asking about his day and grilling him about every moment he's not with you. When your husband mentions that a new account manager started at his firm, you should not follow up with, "Is she pretty?" We all have insecurities but consistently jealous behavior and manipulative comments create obvious wear-and-tear on your relationship.
8. Shirking professional help.
Sometimes working through marriage problems on your own just doesn't work. But don't call it quits until you try resolving your issues with a licensed marriage therapist. These are highly trained professionals who have seen it all and can dole out advantageous advice as well as help you better see your partner's perspective. The sooner you get help, the better. Think of it as going to a dentist of marital health—a small cavity is easy to patch up, while a root canal is an entirely different story.